SOAR-NDT
The Challenge
Name:
SOT-aided NDT Thickness Tool for a Fully-Actuated Aerial Robot
Domain:
NDT contact-based inspection; aerial physical interaction; soft optical tactile sensors
Challenge proposer:
Objectives:
The objective is to develop and integrate an NDT end-effector tool equipped with a SOT sensor, such as https://softroboticstoolkit.com/tactip, for stable contact maintenance in aerial physical interaction. The overall objective breaks down into:
- the mechanical design and integration of the SOT sensor into an NDT end-effector for the fully-actuated miniThex provided by the consortium,
- a software stack compatible with the GenoM-based framework of the miniThex, allowing to use the data stream from the sensor as feedback for stable contact, and
- the experimental validation.
The Solution
Name:
SOAR-NDT – Friction-aware aerial interaction with Soft Optical Tactile feedback for energy-efficient NDT
SOAR-NDT is an autonomous aerial system that brings human-grade touch to non-destructive testing in places people can’t safely go. A soft optical tactile sensor, mounted on a fully-actuated drone alongside a pulsed eddy current probe, lets the robot feel its way onto a surface, hold stable contact under real-world disturbances, and take accurate thickness readings. By combining deep-learning-based contact perception with energy-efficient force control, SOAR-NDT turns aerial inspection from a remote visual check into a genuine hands-on measurement, cutting inspection time, cost, and risk for industries that depend on structural integrity.
Confined-space inspection (ballast tanks, cargo holds, tank interiors) is one of the most dangerous and expensive parts of industrial asset maintenance. Today it still relies on human surveyors working in hazardous, poorly accessible environments, or drones that can only look, not touch, leaving quantitative thickness measurement out of reach for autonomous systems.
SOAR-NDT closes that gap by giving an aerial robot a genuine sense of touch. At its core is a soft optical tactile (SOT) sensor: a compliant, camera-based skin that deforms on infers contact data from the pattern of that deformation in real time. This sensing stack allows the drone to track the surface’s position and orientation as it approaches and touches it, allowing the platform to build and maintain accurate contact even when its exact standoff distance and surface geometry aren’t known in advance.
That perception loop drives an energy-aware controller: rather than rigidly forcing contact, the drone regulates the interaction force it applies, compliantly following the surface while correcting for drift and disturbance. A friction-anchor strategy lets the platform use the natural friction of the contact point to stabilize itself against the surface, reducing the thrust needed to hold position compared to brute-force station-keeping. The result is a robot that can settle onto a wall, tank interior, or hull section, hold a stable, controlled press, and keep a pulsed eddy current probe coupled to the surface long enough to take a reliable thickness reading.
This sensing-and-control stack is mounted on a tilted hexarotor platform, whose independent actuation lets it apply and sustain a contact force against the surface, unlike conventional designs. That decouples flight stability from contact force generation, which is what makes stable, repeatable NDT-quality contact possible in the first place.
The long-term opportunity is one or a fleet of aerial robots that can autonomously survey confined and hard-to-reach structures, taking calibrated, physical measurements rather than just visual footage, removing people from dangerous environments while making inspection faster, more frequent, and more affordable.
The Solution Provider
Volar Robotics is an Italian robotics startup spun out of Sapienza University of Rome, founded by two PhD researchers with a shared vision: giving aerial robots a sense of touch. The team is pioneering soft optical tactile sensing in contact-aware flight control, enabling drones to safely make and hold physical contact with real-world surfaces. By fusing machine learning, tactile perception, and advanced flight control, Volar is building the technology that lets drones move beyond simply observing the world from a distance, opening the door to safer, smarter automation in industrial inspection, maintenance, and beyond.
